New Algorithm to Pinpoint-Land NASA’s Mars Rovers

Improving on awesome isn't necessarily easy. NASA and the Jet Propulsion Laboratory (JPL), with the aid of a new flight control algorithm, will be able to better pinpoint landings of future spacecraft. Imagine.

I thought the landing by NASA and the Jet Propulsion Laboratory of all of the Mars rovers to date has been well, in a word, stellar. The first time around, watching a video of Spirit and Opportunity going through their paces as NASA created the means to achieve an accurate landing was nothing short of amazing. Airbag laden, the rovers literally bounced to a halt on the Mars surface.

Now, landing on the proverbial dime just became easier for future rovers and similar spacecraft. A new and more sophisticated flight control algorithm that allows for even more precise pinpoint landings is a reality.

Figure 1. A Xombie technology demonstrator from Masten Space Systems, Mojave, Calif., ascends from its pad at Mojave Air and Space Port on a test for NASA's Jet Propulsion Laboratory. The vehicle, a vertical-takeoff, vertical-landing experimental rocket, is being used to evaluate performance of JPL's Fuel Optimal Large Divert Guidance (G-FOLD), a new algorithm for planetary pinpoint landing of spacecraft.
(Source: NASA)

Testing of the new Fuel Optimal Large Divert Guidance algorithm (G-FOLD) for planetary pinpoint landing is in the works by JPL. Using Masten Space Systems's XA-0.1B "Xombie" vertical-launch, vertical-landing experimental rocket (See Figure 1), the G-FOLD autonomously generates landing trajectories in real time. It also enables the diverting of the payload during descent -- which was impossible before now.

The G-FOLD algorithms replace algorithms that were used on all of the rovers to date, which had their beginnings with the Apollo program. Unable to both divert accurately during descent and optimize fuel usage, the existing algorithms prevented the targeting of specific targets -- at least doing so accurately. The algorithm will be used in manned and unmanned missions, playing an important fuel-reducing role in both.

Testing of the Xombie involved simulating a course correction whereby G-FOLD flight control software was triggered to calculate a new profile in real time. The result was a whopping success as the rocket was diverted approximately 2,460 feet away from its initial incorrect landing point.

When Spirit and Opportunity launched, I was fortunate enough to attend a showing of the IMAX documentary capturing the experience at The TECH in San Jose. I believe I saw the film another four times. Rough landings, outrageously short windows of launch opportunity, attempts, failures, and ultimately success focused my interest squarely on the Mars Rover program. Now, with the algorithm for greater accuracy in landing -- imagine what this will look like next time around.

I don't think there has been any mistakes. The The new algorithm handles determining the required flight path to land at a chosen site with minimal fuel use. So it is completely independent of the system for choosing the site. I can certainly understand the fuel saving aspects of the new algorithm, but am curious about the addition of in-flight, apparently near real-time navigational changes, as remote in-flight navigational changes will have to be made long before atmospheric insertion. So I am wondering if a separate system is in the works for autonomous landing site corrections (within a limited range around the targeted landing site).

Please ignore that last post - that was one of the stupidest things I've said recently (read in the past week). NASA unfortunately has had its share of major mistakes so I guess I shouldn't infer that they always know what they're doing - history says otherwise.

During the simulation, there was a remote triggering for correction. That's an interesting question as to how it will actually be used. NASA seldom announces anything that isn't well tested/thoughout out. What do you think the mechanism will be for this correction capability?